2,712 research outputs found
Giant dipole resonance with exact treatment of thermal fluctuations
The shape fluctuations due to thermal effects in the giant dipole resonance
(GDR) observables are calculated using the exact free energies evaluated at
fixed spin and temperature. The results obtained are compared with Landau
theory calculations done by parameterizing the free energy. The Landau theory
is found to be insufficient when the shell effects are dominating.Comment: 5 pages, 2 figure
Combined spectral and spatial processing of ERTS imagery data
A procedure for extracting a set of textural features for ERTS-1 MSS data is presented. The textural features were combined with a set of spectral features and were used to develop a classification algorithm for identifying the land use categories of blocks of digital MSS data. The classification algorithm was derived from a training set of 314 blocks and tested on a set of 310 blocks. The overall accuracy of the classifier was found to be 83.5% on seven land use categories
A Repair Framework for Scalar MDS Codes
Several works have developed vector-linear maximum-distance separable (MDS)
storage codes that min- imize the total communication cost required to repair a
single coded symbol after an erasure, referred to as repair bandwidth (BW).
Vector codes allow communicating fewer sub-symbols per node, instead of the
entire content. This allows non trivial savings in repair BW. In sharp
contrast, classic codes, like Reed- Solomon (RS), used in current storage
systems, are deemed to suffer from naive repair, i.e. downloading the entire
stored message to repair one failed node. This mainly happens because they are
scalar-linear. In this work, we present a simple framework that treats scalar
codes as vector-linear. In some cases, this allows significant savings in
repair BW. We show that vectorized scalar codes exhibit properties that
simplify the design of repair schemes. Our framework can be seen as a finite
field analogue of real interference alignment. Using our simplified framework,
we design a scheme that we call clique-repair which provably identifies the
best linear repair strategy for any scalar 2-parity MDS code, under some
conditions on the sub-field chosen for vectorization. We specify optimal repair
schemes for specific (5,3)- and (6,4)-Reed- Solomon (RS) codes. Further, we
present a repair strategy for the RS code currently deployed in the Facebook
Analytics Hadoop cluster that leads to 20% of repair BW savings over naive
repair which is the repair scheme currently used for this code.Comment: 10 Pages; accepted to IEEE JSAC -Distributed Storage 201
High pressure pyrolyzed non-precious metal oxygen reduction catalysts for alkaline polymer electrolyte membrane fuel cells
Non-precious metal catalysts, such as metal-coordinated to nitrogen doped-carbon, have shown reasonable oxygen reduction reaction (ORR) performances in alkaline fuel cells. In this report, we present the development of a highly active, stable and low-cost non-precious metal ORR catalyst by direct synthesis under autogenic-pressure conditions. Transmission electron microscopy studies show highly porous Fe-N-C and Co-N-C structures, which were further confirmed by Brunauer-Emmett-Teller surface area measurements. The surface areas of the Fe-N-C and Co-N-C catalysts were found to be 377.5 and 369.3 m2 g-1, respectively. XPS results show the possible existence of N-C and M-Nx structures, which are generally proposed to be the active sites in non-precious metal catalysts. The Fe-N-C electrocatalyst exhibits an ORR half-wave potential 20 mV higher than the reference Pt/C catalyst. The cycling durability test for Fe-N-C over 5000 cycles shows that the half-wave potential lost only 4 mV, whereas the half-wave potential of the Pt/C catalyst lost about 50 mV. The Fe-N-C catalyst exhibited an improved activity and stability compared to the reference Pt/C catalyst and it possesses a direct 4-electron transfer pathway for the ORR process. Further, the Fe-N-C catalyst produces extremely low HO2- content, as confirmed by the rotating ring-disk electrode measurements. In the alkaline fuel single cell tests, maximum power densities of 75 and 80 mW cm-2 were observed for the Fe-N-C and Pt/C cathodes, respectively. Durability studies (100 h) showed that decay of the fuel cell current was more prominent for the Pt/C cathode catalyst compared to the Fe-N-C cathode catalyst. Therefore, the Fe-N-C catalyst appears to be a promising new class of non-precious metal catalysts prepared by an autogenic synthetic method. © The Royal Society of Chemistry 2015.
Health, Technical Efficiency And Agricultural Production In Indian Districts
In this study, we attempt to quantify the effect of improved population health on technical efficiency in agricultural production. Using data for over 260 districts in 15 Indian states, we employ the random-coefficients technique to estimate a Cobb-Douglas production function, computing overall and input specific technical efficiencies for each district. We then model health (the district infant mortality rate) as a determinant of (in) efficiency in a second stage, controlling for a range of other socioeconomic variables. We find that decreases in the infant mortality rate, as well as increases in the literacy rate and level of irrigation, are associated with significant increases in overall technical efficiency, and that a good portion of healths effect is probably due to improvements in the efficiency of labor use. While efficiency increases from improvements in irrigation and literacy are larger, the potential gains from health are still fairly substantial.technical efficiency, Random coefficients model, the frontier production function
Crop classification using airborne radar and LANDSAT data
Airborne radar data acquired with a 13.3 GHz scatterometer over a test-site near Colby, Kansas were used to investigate the statistical properties of the scattering coefficient of three types of vegetation cover and of bare soil. A statistical model for radar data was developed that incorporates signal-fading and natural within-field variabilities. Estimates of the within-field and between-field coefficients of variation were obtained for each cover-type and compared with similar quantities derived from LANDSAT images of the same fields. The classification accuracy provided by LANDSAT alone, radar alone, and both sensors combined was investigated. The results indicate that the addition of radar to LANDSAT improves the classification accuracy by about 10; percentage-points when the classification is performed on a pixel basis and by about 15 points when performed on a field-average basis
Enhanced alpha-amylase production using Streptomyces gancidicus ASD by process optimization
845-852The present study was focused on purification and optimization of amylase from marine actinomycetes. Among 101 actinomycetes isolates from Andaman & Nicobar islands, Streptomyces sp gancidicus_ASD was isolated and further studied. The enzyme activity was studied at various physical parameters like temperature, pH, carbon source, Nitrogen source, metal ions, NaCl concentration etc. by maintaining all the factors with 100 ml of crude extract. Also, media optimization with response surface methodology was used to ameliorate the bioprocess economics. A central composite design was conducted to optimize the four selected factors. Statistical analyses of the data of model fitting were done by using Design expert 10.0 (stat-Ease). Results show a maximum predicted amylase yield of 11460.34 IU/ml when using 1.05% sucrose, 0.608% beef extract, 7.1 pH and 40.35 °C temperature. The predicted value is approximately 1.24-fold much higher than the original production (9248 IU/mL) determined by the conventional one-factor-at-a-time optimization method which can be applied in bioprocess for increased amylase yield
ANTICANCER ACTIVITY OF POLYMERIC NANOPARTICLES CONTAINING ETOPOSIDE USING ALBINO RATS AS EXPERIMENTAL ANIMAL MODEL
Objective: Etoposide is a potent anticancer drug and a major limiting factor that hinders therapeutic use as its high levels of systemic circulation often associated with various off-target effects, particularly cardiotoxicity. The present study focuses on the evaluation of the anticancer activity of optimized etoposide nanoparticles compared with marketed etoposide formulation in experimental animal models.Methods: Albino rats (180–200 g) were used for the study. The anticancer effect of the formulated etoposide nanoparticles was evaluated by induction of hepatocellular carcinoma (HCC). The animals housed in cages and kept on a 12 h light/dark cycle. Following the acclimatization for 1 week, HCC will be induced in rats by adding 100 mg/L of diethylnitrosamine (DENA) in drinking water for 8 weeks. Drug treatment (etoposide [9 mg/kg] in 0.5 % carboxymethyl cellulose; p.o.) can be started at the end of 1 week after cancer induction and dose of 9 mg/kg of etoposide and lyophilized nanoparticles will be administered through oral route on 1, 7, 14, 21, and 28 days. Nanoformulations were evaluated in healthy rats, and anticancer activity was studied in DENA treated rats.Results: The results showed that the polymeric nanoparticles containing etoposide was screened for its anticancer activity by counting the liver nodules of rats with hematoxylin and eosin stain when comparing control and etoposide-treated group.Conclusion: The results of the study concluded that in rats treated with nanoformulations, the numbers of liver nodules were found to be significantly reduced
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